former grand champion's 60th birthday ring-entering ceremony
A special sumo ceremony where a former yokozuna performs the dohyō-iri on his 60th birthday, often wearing a red kesho-mawashi.
The other day, the former grand champion's 60th birthday ring-entering ceremony was held at the Kokugikan.
Compound of 還暦 (kanreki, '60th birthday') + 横綱 (yokozuna, 'grand champion') + 手数入り (dezūri, 'ring-entering ceremony').